Abstract: An expandable band is employed to provide a mold on the interior of the joint into which the weld puddle is flowed which may be made of any appropriate material, but preferably is copper. The back-up band is carried on a set of rounding jacks which engage the facing pipe ends and exert a circumferentially uniform radial force on the pipes. This serves to round the ends equally and bring them into coaxial alignment with each other in the vicinity of the joint. The back-up band bridges the joint and expands to form a closed or semi-sealed chamber around the joint.

Abstract: A TIG pipe welding method which employs two sets of machine guide surfaces on the pipe ends. First radially inner guide surfaces cooperate with a sensor coupled to the welding torch to continuously monitor the arc gap between the welding electrode and the weld puddle as the welding electrode moves around the circumference of the pipe. The second set of radially outer surfaces cooperate with a welding carriage to guide the carriage and welding modules around the pipe joint. The carriage is constructed to provide a sealed welding chamber surrounding the electrode. An additional flow of shielding gas is provided around the torch electrode of a TIG or hot wire TIG welding module to augment the normal gas shield.

Abstract: The sea sled includes a pair of pontoons mounting depending rollers for straddling a pipeline disposed on the sea bottom. Water jets fluidize the sea bottom to form a trench in which the pipeline settles. The slurry formed by the water jets is removed from the trench by the eductor system which includes a pair of conduits each having a suction inlet at its lower end for location within the trench, a discharge at its upper end, a pair of pump nozzles each having an inlet external to the associated conduit and an outlet within the conduit directed toward the corresponding discharge, and a pair of primary nozzles respectively spaced from the inlet ends of the pump nozzles. A high pressure, low volume, fluid is pumped from the surface through the jet nozzles. The fluid emanating from the jet nozzles entrains ambient fluid and delivers low pressure, high volume, fluid through the respective pump nozzles to their corresponding discharges.

Abstract: A pair of pipe ends are first prepared prior to welding to provide highly accurate guide surfaces. Secondly, a welding torch carriage arrangement is provided which engages the exterior surfaces of the abutting pipe ends to be welded, which carriage is guided around the circumference of the pipe ends in conjunction with the guide surfaces provided thereon. Thirdly, a back-up band arrangement is provided interiorly of the joint to be welded.An expandable band is employed to provide a mold on the interior of the joint into which the weld puddle is flowed which may be made of any appropriate material, but preferably is copper. The back-up band is carried on a set of rounding jacks which engage the facing pipe ends and exert a circumferentially uniform radial force on the pipes. This serves to round the ends equally and bring them into coaxial alignment with each other in the vicinity of the joint. The back-up band bridges the joint and expands to form a closed or semi-sealed chamber around the joint.